EP-A-0720816 discloses a process for the manufacture of a natural, curved sausage product comprising co-extruding at least two meat doughs, and providing the co-extruded dough with a skin. At least one of the meat doughs is extruded through a venturi such that the fibres are randomised, and at least are one dough is extruded such that the fibres are substantially aligned. The two doughs are co-extruded side-by-side, so that on subsequent cooking, the different fibre orientations in the two doughs cause differential shrinkage of the doughs, thereby giving rise to curving of the product.
EP-A-0024790 discloses apparatus for co-extruding an inner core of meat with an outer, annular layer of fat emulsion. The apparatus comprises a stuffing horn and a nozzle which is fitted to the downstream end of the stuffing horn. Said stuffing horn comprises two co-axial tubes which define an inner conduit for the meat and an outer, annular conduit for the fat emulsion. The meat and fat are admitted to the stuffing horn at an upstream end using separate mechanical pumps. The extrusion head similarly defines two co-axial conduits which communicate with the corresponding conduits in the stuffing horn. The co-extruded product debouches from the extrusion head into a flexible, plastics casing which encircles the stuffing horn and extrusion head.
With reference to the stuffing horn, the innermost tube is supported in the interior of the outermost tube by means of a plurality of circumferentially spaced spacers or vanes. These vanes thus constitute obstacles in the path of the fat emulsion through the stuffing horn. As will be well known in the art, fat and meat emulsions of the kind which are generally employed in apparatus of the kind disclosed by EP-A-0024790 comprise fibrous meat or fat components and emulsifier(s). A problem which has been observed in co-extruded products manufactured using the apparatus of EP-A-0024790 is that there is a tendency for the outer fat emulsion layer to split in the direction of extrusion during cooking. It is thought that this splitting may be caused by a lack of cohesion between adjacent fibres in the emulsion that have been streamlined by passage over the vanes in the outer conduit of the stuffing horn, and by the depletion of such fibres in longitudinal zones within the emulsion downstream of the spacers.
An object of the present invention is to solve or at least alleviate this problem. Specifically, it is an object of the present invention to provide means for manufacturing a co-extruded meat product having a core of a first extrudable food substrate and one or more contiguous outer layers of the same or different extrudable food substrates disposed wholly or partly around the core, wherein at least one of the outer layers consist of fibrous meat or fat emulsion, which co-extruded meat product has a reduced tendency for splitting of the meat or fat emulsion layer when the product is cooked.